(a) Field of the Invention
The present invention relates to a rear suspension system of a coupled torsion beam. More particularly, the present invention relates to a rear suspension system of a coupled torsion beam of which a connecting structure of a torsion beam and a trailing arm is improved.
(b) Description of the Related Art
Generally, even though the suspension system of a torsion beam axle type (CTBA; Coupled Torsion Beam Axle) has simple components and narrow performance in a design, it has high driving stability compared to the low production cost and the light mass such that it can be mainly applied to a smaller car and a semi-mid-size car.
In the suspension system of the torsion beam axle type, as shown in FIG. 1, a torsion beam 101 is disposed in width direction of a vehicle body, and a trailing arm 105 that is mounted with a carrier 103 for connecting a wheel and a tire is connected thereto.
Each trailing arm 105 is provided with a shock absorber 107 and a bushing 109 for being connected to a vehicle body and a spring 113 is mounted between a spring seat 111 and the vehicle body.
The wheel moves according to the torsion deformation of the torsion beam 101 in the middle of the suspension system of the torsion beam axle type according to the conventional art, and the wheel is induced to toe-in by the deformation of the torsion beam 101, the position of the trailing arm 105, and the characteristic of the mounting bushing 109.
Referring to FIG. 2, in the rear suspension system of a coupled torsion beam, the trailing arm 105 may be formed by connecting an inner arm 106a and an outer arm 106b by welding to be formed as tubular shape for high performance and light weight.
The torsion beam 101 may be “V” shape and be connected to trailing arm 105 for high performance and light weight.
However, when the rear suspension system of a coupled torsion beam absorbs twisting the torsion beam 101, warping may be generated and thus concentrated stress may be applied to a connecting portion 1 of the torsion beam 101 and the trailing arm 105.
Thus, if the torsion beam 101 is twisted in driving of a vehicle, the warping formed to the connecting portion 1 of the torsion beam 101 and the trailing arm 105 may influence fatigue life of the suspension system.
As solving the problem, increasing thickness where the warping may be applied may be considered, however entire weight of the suspension system is increased.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.